Navigating and controlling vehicles, such as an aircraft, is a difficult and complicated process. Whether the aircraft is operated manually by a pilot or operated automatically, such as an unmanned aerial vehicle, operation of the aircraft can be complicated by many factors. Poor weather conditions, such as storms, fog, hail, downdrafts, darkness, and high winds, reduce visibility and impact the performance of the aircraft. Operation of the aircraft can also be affected by the specific geography and surrounding of the location of operation. For example, operating an aircraft in crowded or high risk environments, such as an emergency response location, a ship, an offshore oil drilling platform, requires precise and accurate control to reduce safety risks, such as collision. This is especially true when the aircraft is performing sophisticated maneuvers such as landing, aerial docking, or aerial refueling.
To increase the safety of aircraft operation, systems have been developed to assist with navigation, control, landing, and aerial refueling. These systems include global positioning systems (GPS), radio navigational systems, inertial navigation systems (INS), non-directional beacons (NBD), optical navigation systems, and laser navigation systems. Laser navigation systems have certain advantages over other types of systems. For instance, laser navigation systems are self-contained, and operate in poor weather conditions and environments where other systems cannot operate.
However, existing laser navigation systems are too large for some applications in particular mobile applications. Typically, navigation beacons for aerial applications use intensity modulated 405 nm laser diodes, or a 1.55 um fiber laser with bulk optics for beam shaping and a two axis galvanometer for beam deflection. These systems tend to be in one or two large boxes to contain the laser sources and a separate unit for the bulk optics and control electronics.
In addition, the laser power generated is too low to transmit navigation information to the desired distances, such as 6,000 feet or more. Generally, existing systems cannot generate a tight enough formed beam to achieve signal levels on the outer periphery of the pattern.
Also, the optics in existing systems are not capable of maintaining proper performance over long distances, which reduces the operational range of the system. Typically, the beam forming optics are incapable of maintaining the correct shape over long propagation distances, especially for the widely divergent sections of the beam. If the beam is aberrated or distorted, the signal intensity that the incoming aircraft receives is reduced, which degrades the SNR, and reduces the range over which the system can operate.